The present invention relates to devices for attaching lifting mechanisms to containers or the like, and in particular to containers provided with pre-formed apertures therein, such as those in the corner fittings of standard freight containers.
Standard freight containers are provided with corner fittings, each of which comprises a hollow, generally box-shaped component provided with apertures in the outwardly facing walls thereof for receiving therein releasable securing means. Hereinafter, any reference to a corner fitting is to be understood as referring to a corner fitting of the above described type.
Whereas bottom corner fittings of such freight containers are primarily used for locating and securing the containers to transporting surfaces and to each other, using twistlocks or other locking means extending through the generally rectangular or elliptical apertures in the corner castings, the upper corner fittings are such as to permit lifting and maneuvering of the containers.
More particularly, such lifting is usually achieved using a spreader equipped either with built-in twistlocks adapted to be received in the apertures in the upper walls of the upper corner fittings or with hooks which pass through the apertures in the upper walls of the upper corner fittings and through the apertures in the end walls of said corner fittings, said latter apertures commonly being known as `hook holes`. The interiors of the upper corner fittings between the apertures in the upper walls and the end walls are shaped to accommodate the hooks, as are the hook holes themselves. Said hook holes are each of only slightly asymmetrical shape with no significant difference between the lengths of the major and minor axes and with little flat purchase area therearound within the fittings.
There is currently a need for a device to enable lifting of containers by attachment of lifting frames to the end faces of the containers, and in particular by way of the apertures in the end walls of the upper corner fitting
However, it will be appreciated that, because of the particular shape of the apertures in the end walls of the corner fittings, it is not practical to use conventional twistlock-type mechanisms to effect attachment of the lifting mechanisms to the containers because of the limited purchase area available within the fittings for engagement by the heads of the twistlocks.